Biomedical subjects

C J Marsolek

Publications and source records attributed to C J Marsolek.

3 recordsLinked to original sources

PubMed1992

Categorical versus coordinate spatial relations: computational analyses and computer simulations.

Results of 4 sets of neural network simulations support the distinction between categorical and coordinate spatial relations representations: (a) Networks that were split so that different hidden units contributed to each type of judgment performed better than unsplit networks; the reverse was observed when they made 2 coordinate judgments. (b) Both computations were more difficult when finer discriminations were required; this result mirrored findings with human Ss. (c) Networks with large, overlapping "receptive fields" performed the coordinate task better than did networks with small, less overlapping receptive fields, but vice versa for the categorical task; this suggests a possible basis for observed cerebral lateralization of the 2 kinds of processing. (d) The previously observed effect of stimulus contrast on this hemispheric asymmetry could reflect contributions of more neuronal input in high-contrast conditions.

Computer Simulation↗

PubMed1992

Form-specific visual priming in the right cerebral hemisphere.

Results of 4 experiments indicate that both within-modality and case-specific visual priming for words are greater when test stimuli are presented initially to the right cerebral hemisphere (RH). In contrast, neither within-modality nor case-specific explicit memory for words is greater when stimuli are presented initially to the RH. Priming is measured using word-stem completion, and explicit memory is measured using word-stem cued recall. In both cases, Ss first rate how much they like words, and then word stems are presented briefly to the RH (in the left visual field) or to the left hemisphere (in the right visual field). Results suggest that at least 2 separate systems encode the visual representations that produce priming. The system that is more effective in the RH is better at representing form-specific information, whereas another system that is not more effective in the RH does not distinguish among distinct instances of word forms.

Adult↗

PubMed1990

Causality and the allocation of attention during comprehension.

Recent research has suggested that each statement in a narrative text is understood by relating it to its causal antecedents and consequences and that the text as a whole is understood by finding a causal path linking its opening to its final outcome. Fletcher and Bloom (1988) have proposed that in order to accomplish this goal, while minimizing the number of times long-term memory has to be searched, readers focus their attention on the last clause of a narrative that has causal antecedents but no consequences in the preceding text. As a result, a statement that is followed by a causal antecedent should remain the focus of attention, while the same statement followed by a consequence should not. This prediction was tested and confirmed in three experiments which show that when a target statement is followed by a sentence that includes only causal antecedents, (a) continuation sentences related to it are read more quickly, (b) target words drawn from it are easier to recognize, and (c) subject-generated continuations are more likely to be causally related to it.

Attention↗